For safety reasons, inboard motorboat engines are equipped with engine covers to protect persons in the boat from the heat of the engine. Such engine covers are typically made from injection molded plastic, and are supplied by the engine manufacturer together with the engine itself.
Such standard plastic engine covers suffer from numerous disadvantages. First, plastic is not a rigid material. Therefore, such engine covers are typically injection molded with a plurality of baffles/interior walls on their underside to give the engine cover sufficient rigidity.
An example of a standard plastic injection molded cover for a Mercury™ 496 MAG/MAG HO motor is show in FIGS. 1 and 2. As can be seen in the top perspective view of FIG. 1, cover 10 has air holes 12 passing therethrough.
As can be seen in the bottom perspective view of FIG. 2, holes 12 are surrounded by walls 14 therearound. Walls 14 add strength to cover 10. Unfortunately, walls 14 also act as air baffles, trapping pockets of heated air under cover 10. As a result, walls 14 interfere with the free flow of air around the top of the engine, thus impeding engine cooling.
In addition, cover 10 also has a single continuous side wall 16 passing therearound. Side wall 16 also adds strength to cover 10, especially at the edges of cover 10. However, side wall 16 also acts to trap a pocket of heated air under cover 10.
A further disadvantage of plastic cover 10 is that it does not conduct heat away from the engine, nor does it dissipate heat from the engine.